Indigenous chicken breeds have both cultural significance and economic value since they possess unique genetic characteristics that enable them to adapt to the local environment and contribute to biodiversity, food security, and sustainable agriculture in Vietnam. To (Tò in Vietnamese) chicken, a Vietnamese indigenous chicken breed, is popularly raised in Thai Binh province; however, little known is about the genetic diversity of this breed. In this study, we sequenced the complete mitochondrial genome of To chicken for a better understanding of the diversity and origin of the breed. The results of sequencing showed that the mitochondrial genome of To chicken spans a total length of 16,784 base pairs and comprises one non-coding control region (known as the displacement-loop (D-loop) region), two ribosomal RNA genes, 13 protein-coding genes, and 22 transfer RNA genes. The phylogenetic tree analyses and estimated genetic distances based on 31 complete mitochondrial genome sequences indicated that To chicken has a close genetic distance with the Laotian native chicken breed, Lv’erwu breed in China, and Nicobari black and Kadaknath breeds in India. The result of the current study might be important for conservation, breeding, and further genetic studies of To chicken.

This study was conducted to assess the impact of embryonic developmental stage and synchronization protocol on the efficiency of in vitro Cỏ goat embryo transfer. The results revealed that the transfer of three Cỏ goat blastocysts per recipient produced outcomes comparable to the transfer of nine zygotes per recipient. Moreover, pregnancy rates evaluated at Day 30 and Day 60 of gestation were significantly higher in the blastocyst group than in the zygote group (P < 0.05). Parameters such as oestrus rate, onset and duration of oestrus, number of follicles per recipient, and number of corpora lutea per recipient, as well as the number of pregnant recipients at Days 30 and 60 of gestation, were all greater when synchronization was achieved using CIDR, PGF2α, oestradiol benzoate, and GnRH compared with the combination of PGF2α and GnRH alone. In conclusion, these findings suggest that the use of Cỏ goat blastocysts for embryo transfer into recipients synchronized with CIDR, PGF2α, oestradiol benzoate, and GnRH significantly enhances the efficiency of in vitro Cỏ goat embryo transfer.

In this study, we investigated the effect of donor cell passage number, lineage, and sex on the efficiency of cloned embryo transfer in the endangered Vietnamese Ỉ pig. Cloned Ỉ pig embryos were generated using somatic cell nuclear transfer technology. In Experiment 1, Ỉ pig fibroblasts (ID:6004) at the 5^th and 6^th passages resulted in significantly higher pregnancy, farrowing, and piglet production rates compared with those at the 4^th and 7^th passages. In Experiment 2, pregnancy, farrowing, and piglet production rates did not differ significantly between donor cell groups of male and female origin (P > 0.05). Among cloned Ỉ piglets that died within the first week postpartum, the number of female piglets was marginally higher (1/4 vs 0/4, P > 0.05). In Experiment 3, statistical analyses revealed no significant differences in pregnancy rates, farrowing outcomes, or one-week survival of live cloned piglets across the three donor cell lines (IDs: 6004, 9154, and 9157) (P > 0.05). These findings demonstrate that donor cell passage number is a critical factor influencing the efficiency of cloned Ỉ pig embryo transfer, whereas donor cell sex and cell line identity exert no significant effect.